Unable to delete specific records using order by for multiple columns [duplicate]

admin

4 years ago

CREATE TABLE SAMPLE1
(
     CN VARCHAR(MAX),
     CR VARCHAR(MAX), 
     DN VARCHAR(MAX),
     DR VARCHAR(MAX),
     DMR VARCHAR(MAX)
)

INSERT INTO SAMPLE1 VALUES ('C1', 'A', 'D1', '--', '--')
INSERT INTO SAMPLE1 VALUES ('C1', 'B', 'D1', '-A', '--')
INSERT INTO SAMPLE1 VALUES ('C1', 'E', 'D2', '--', '--')
INSERT INTO SAMPLE1 VALUES ('C1', 'C', 'D1', '-A', '--')
INSERT INTO SAMPLE1 VALUES ('C1', 'D', 'D3', '--', '--')
INSERT INTO SAMPLE1 VALUES ('C1', 'F', 'D2', '--', '--')
INSERT INTO SAMPLE1 VALUES ('C1', 'F', 'D2', '-A', '--')

Expected result:

('C1', 'F', 'D2', '-A', '--')

i.e last record from SAMPLE1.

I tried with the following query, but it doesn’t work:

DELETE t
FROM  
    (SELECT 
         ROW_NUMBER() OVER(PARTITION BY CN
                           ORDER BY CR, DR, DMR DESC) AS r
     FROM SAMPLE1) t
WHERE r > 1